Dams, pollution, deforestation, and urban sprawl have all taken, and continue to take, their toll on streams used by migrating fish, such as salmon and steelhead trout. Many migrating fish, such as certain species of Pacific salmon and other anadromous fish are now on the endangered list.
Impediments or obstructions, such as dams or culverts, have effectively blocked or greatly hindered upstream migration for many returning fish. Attempts to remedy this include fish ladders and complex and costly underground piping systems that run the length of migrating streams. Most of these systems or apparatus are costly and cannot be readily removed. Additionally, with most of these systems, the migrating fish generally must jump to avoid swing against great fluid pressure created by the differential of the head of the fluid level between the after-impediment water level and the pre-impediment water level. Typically, a series of height staggered concrete boxes are used to allow the fish to jump to the next height level. This causes the fish to be damaged, or at least, greatly exhausted. It is believed that the condition of the fish at the spawning location greatly impacts the long-term viability of the particular fish species.
Because fish migration is generally seasonal, depending on the species of fish, it is desired to have a portable, relatively inexpensive apparatus for transporting migrating fish past river or stream impediments that also reduces the flow rate on the migrating fish during differential fluid level acclimation.
The present invention relates to an apparatus for reduced flow rate fish passage to the fish as they swim against the current, resulting in the fish being less likely to be injured as they migrate past obstructions. Additionally, the method and apparatus for reduced flow fish passage of the present invention is economical, portable, and can be used for fish passage in both directions, i.e., upstream and downstream The present invention is much less costly than conventional fish ladders, requires little maintenance, and is portable. Additionally, the present invention is environmentally compatible by being less disruptive than conventional permanent piping systems and fish ladders. The present invention requires only enough water flow to attract the migrating fish to a submersible entry and the fish need only to expend the energy to overcome the present internal (acclimation) flow.
The present invention provides an apparatus for reduced flow rate fish passage, comprising a passage unit having a tubular passageway or pipe, an upstream valve and a downstream valve being used to close off said passageway at or near each end of said passage unit, an alternative passageway and a fabricated base, said fabricated base supporting said passageways and aiding in spacing and supporting said pair of valves. The pair of valves have an opening, a closing means, a valve stem, and en operator to close off said opening. The passage unit is installed essentially parallel to and below the surface of a water body and adjacent to an obstruction of which the fish must pass. The pair of valves are synchronized for two-stage opening. An optional valve is provided, which optional valve is a main shut-off valve. The apparatus for reduced flow rate fish passage has an access pipe. The apparatus for reduced flow rate fish passage has passageway sensors to send a signal to a remote controller for cycling of said upstream valve and said downstream valve. The upstream valve and downstream valve are of a variety of types of valves, such as a knife gate valve, an iron gate valve, a ball gate, or check gate, or any other valve that will close a cross-sectional opening and are capable of being manually controlled and operated or remotely pneumatically controlled. The apparatus for reduced flow rate fish passage has the passageways being extended to, through, or over said obstruction. The apparatus for reduced flow rate fish passage has a conventional attraction flow device.
It is therefore an object of the present invention to provide an apparatus for reduced flow rate fish passage that is relatively inexpensive and easily manufactured.
It is therefore a further object of the present invention to provide an apparatus for reduced flow rate fish passage that is relatively easily transported and moved as conditions require.
It is therefore a further object of the present invention to provide an apparatus for reduced flow rate fish passage that is adaptable for use with any type of obstruction to fish migration.
It is therefore a further object of the present invention to provide an apparatus for reduced flow rate fish passage that does not injure migrating fish as they pass obstacles in their migration.
These and further objects are satisfied by the apparatus for reduced flow rate fish passage of the present invention.